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At the Chicago Network’s Women in the Forefront Luncheon Friday, Kraft CEO Irene Rosenfeld urged the predominantly female crowd to make a difference at work, take risks and ask for what they want.

It was a seldom-seen, joke-cracking side of Rosenfeld, who is known for her stoicism. Forbes’ Most Powerful Woman in Business began her remarks with a hearty laugh because her MBA had been described in an introduction as a “masters in benefits administration.”

She also shared her most frequently asked question — usually asked by men: “Why would you want to run a company that’s smaller?” — in reference to her plan to spin off Kraft’s $18 billion North American Grocery business this year, leaving Rosenfeld with the $36 billion global snacks business.

“When are you guys ever understand that size isn’t the big deal?” Rosenfeld said, to a big round of laughs.

As an example for making a difference at work, Rosenfeld pointed to her decision to break up the Northfield-based company. Saying that since returning to Kraft in 2006, she had orchestrated “the big cheese of all turnarounds” that she might have been content to remain “at the middle of the heap.”

“We wanted to be at the top,” Rosenfeld said. She noted that both companies will be based in the Chicago area. The grocery business will remain in Northfield while the snacks company will be in Deerfield.

In response to a round of applause, she said, “Mayor (Rahm) Emanuel is not cheering quite as loudly.” Rosenfeld said at a luncheon last fall that Kraft was in talks with the Mayor’s office about a possible Chicago headquarters.

Her hostile takeover of Cadbury, completed in 2010, was an example of risk taking. Rosenfeld famously butted heads with Kraft investor Warren Buffett during the process and dealt with the British media’s “intense interest” in her personal life. However, she said, the benefits of the acquisition have outstripped Kraft’s expectations.

As for “asking for what you want,” Rosenfeld pointed to a routine dinner with a supervisor in 1996 in which she was asked what she wanted to do in the future.

Rosenfeld told him that she would like to run an independent business and received an offer three weeks later to run Kraft’s Canadian business.

“If I had not spoken up, it’s unlikely would have landed one of the most satisfying jobs of my career,” she said.

A mother of two adult daughters, Rosenfeld addressed the work/life balance issue, saying that she had involved her children in work, talking about it at dinner, bringing product samples home and taking them to commercial shoots when possible. She also encouraged mothers to take time for themselves, adding that she plays piano and exercises to relax.

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